I think this is for if the keys of the values dict are column locations instead of labels:

```python
In [46]: df = DataFrame({'A': ['a', 'b', 'c'], 'B': ['a', 'e', 'f']})

In [47]: d = {0: ['a']}

In [48]: df.isin(d, iloc=True)
Out[48]: 
       A      B
0   True  False
1  False  False
2  False  False
```